title: Persistence of human herpesvirus 6 according to site and variant: possible greater neurotropism of variant A.
abstract: Little is known of the persistence and pathogenicity of human herpesvirus 6 (HHV-6) after primary infection, including the role of strain variant. Over 2 to 5 years, 2,716 children and 149 families were studied. Peripheral blood mononuclear cell (PBMC), saliva, and cerebrospinal fluid (CSF) specimens were examined for HHV-6 DNA and variant. Ninety-nine percent of isolates causing primary infection were HHV-6 variant B (HHV-6B), which predominated in 95%-98% of the variants persisting in PBMC and saliva specimens from children and adults. Of 668 CSF samples, 13% contained HHV-6 DNA; of 77 children examined after primary infection, 61% had HHV-6 DNA detected only in their CSF and 39% had HHV-6 DNA in both CSF and PBMCs. HHV-6 variant A (HHV-6A) was detected significantly (P = .0001) more frequently in CSF than in PBMCs or saliva. In children for whom HHV-6 was identified in both CSF and PBMCs, PBMCs contained only HHV-6B, while CSF contained HHV-6A or HHV-6B, not both. Thus, in patients with dual infection, only HHV-6A persisted in CSF, which suggests that HHV-6A has greater neurotropism. Findings for adults indicate that dual infection occurs; variant persistence is similar to that for children. The frequency of HHV-6A infection increased little with age, thereby indicating that HHV-6A infection remains uncommon into adulthood. This study suggests that HHV-6 variants have different immunobiologic courses and neurotropism.
authors.affiliation: Department of Pediatrics, University of Rochester School of Medicine and Dentistry, New York 14642, USA.
authors.forename: C B
authors.initials: CB
authors.lastname: Hall
authors.forename: M T
authors.initials: MT
authors.lastname: Caserta
authors.forename: K C
authors.initials: KC
authors.lastname: Schnabel
authors.forename: C
authors.initials: C
authors.lastname: Long
authors.forename: L G
authors.initials: LG
authors.lastname: Epstein
authors.forename: R A
authors.initials: RA
authors.lastname: Insel
authors.forename: S
authors.initials: S
authors.lastname: Dewhurst
mesh_terms: D000328:Adult; D001921:Brain / Q000821:virology*; D002675:Child, Preschool; D004279:DNA, Viral / Q000032:analysis; D006566:Herpesviridae Infections / Q000821:virology*; D015654:Herpesvirus 6, Human / Q000145:classification* / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007963:Leukocytes, Mononuclear / Q000821:virology; D012463:Saliva / Q000821:virology
chemical_list: D004279:DNA, Viral